GOod advice, keep it coming.
I just copied and pasted this from the DMV motorcycle manual:
BRAKING
Your motorcycle has two brakes: one each for the front and rear wheel. Use both of them at the same time. The front brake is more powerful and can provide at least three-quarters of your total stopping power. The front brake is safe to use if you use it properly.
Remember:
* Use both brakes every time you slow or stop. Using both brakes for even "normal" stops will permit you to develop the proper habit or skill of using both brakes properly in an emergency. Squeeze the front brake and press down on the rear. Grabbing at the front brake or jamming down on the rear can cause the brakes to lock, resulting in control problems.
* If you know the technique, using both brakes in a turn is possible, although it should be done very carefully. When leaning the motorcycle some of the traction is used for cornering. Less traction is available for stopping. A skid can occur if you apply too much brake. Also, using the front brake incorrectly on a slippery surface may be hazardous. Use caution and squeeze the brake lever, never grab.
* Some motorcycles have integrated braking systems that link the front and rear brakes together by applying the rear brake pedal. (Consult the owner's manual for a detailed explanation on the operation and effective use of these systems.)
http://www.nydmv.state.ny.us/mcmanual/mcmanual.htm
Everything that you have quoted from NY DMV is the MSF standard and sorry to say. Out of date.
It was written by folks who understood the bikes of the time, with knowledge gleaned from years of riding cruisers, standards, and OK maybe the "Cafe' Racers" of the age. Their teaching here was aimed at folks who NEVER used their front brakes. (Cruiser Types and other mental midgets). The language used was an attempt to get folks to start using that front brake in a time when many folks were swearing up and down that the front brake will cause you to crash. Same with the MSF’s insistence on 4 fingers covering clutch and front brake. Which in itself is a hazard with today’s brakes being as powerful as they are all you need is a young riding panic braking and grabbing a FIST full of front… How about two fingers of front instead? Even in a panic it gives the bikes more time to transfer weight to the front.
Is the Rear brake going to provide 25% of your braking? Never, not when you are REALLY trying to stop in a hurry. The front to rear ratio of modern front end biased sport bike is going to be something like 90/10 or in MANY cases under hard braking 100/0 front to rear.
Watch some of your buddies next time you're up in the twisties playing hard or at a track day and see how much air is under that rear tire under MAX braking sometimes. Other times it has been my experience that the rear is so light, so barely in contact with the asphalt that applying more than just a feather touch of rear brake causes it to lock up, Yes even the Hayabusa's weak rear.
So while saying that the Hayabusa's rear brake is useless may not be 100% accurate. It is safe to say that liberal use of the rear and counting on the rear in an emergency stopping situation can frequently lead to tears. The best thing you could do, is forget all about your rear brake for the first few months you're out rolling around. Get comfortable using your fronts HARD! Giving them that half second squeeze to load the front end is crucial, but once you get really comfortable with your fronts you will out brake 90% of your riding buddies, in all conditions all the time.
There have been several times in the past were someone I was riding with blows a corner or a turn, because they weren't able to bleed off enough speed, while myself and a few others were able to make the turn easily and without drama even though we had been carrying a higher speed. It's simply about trusting that front brake and learning where the limits are. I've seen lots of guys using both front and rear brakes not able to stop for shid simply because they have NEVER gotten used to really trusting the front. They leave long black skid marks off the rear as they fumble around hoping things come to a halt. They start slowing 100 feet earlier for a corner than the rest of the crowd and will usually brake two or three more times right up to the apex upsetting the whole machine.
So the Rear is useful, you bet. Holding you in place on a hill, in dirt or gravel where you need to NOT use the front, in parking lots below 10 mph, and yes to settle in the bike entering a corner... But all of these rear brake techniques while nice and helpful will not save your life.
The Front brake will...
So master it. Become a demon on the fronts...
Just watch out for Ice, snow, and gravel. Those are trouble with a bike period, more so with the front brakes. Rain isn't a concern, just allow the bike time to load the front.